The central part of polymethylmethacrylate (PMMA) lens was modified to be hydrophobic and the peripheral part, to be hydrophilic by photochemical reaction with ArF excimer laser and chemicals. PMMA has a high–transmittance property in the visible light and has been used as an intraocular lens. However, protein and fat are stuck onto the lens surface after a long-term insertion, which makes the surface get opaque; that is the after-cataract.
Accordingly, the central part of the lens was modified to be hydrophobic in order to protect the PMMA lens from fat and protein. And, the peripheral part was modified to be hydrophilic to develop an affinity for the tissue. Firstly, the central part of the lens was irradiated with ArF laser (147kcal/mol) in the presence of fluorine oil (perfluoropolyether) or CFn gas ambience. By this photochemical reaction, the CF3 functional group was substituted on the PMMA surface. Secondly, the peripheral part of the lens was irradiated with ArF laser (147kcal/mol) in the presence of water. By this photochemical reaction, the OH functional group was substituted on the PMMA.
The contact angle with the physiological salt solution was measured. The contact angle of the non-treatment sample was 83 degrees. The one treated with perfluoropolyether was 117 degrees at the laser shot number of 5000 and the laser fluence of 25 mJ/cm2. When using CBrF3 and CClF 3, the contact angles were both 91 degrees at the laser shot number of 5 and the laser fluence of 20 mJ/cm2. And, the one using the water was 14 degrees, less than the contact angle of the non-treatment sample.
It was confirmed that the exposure part of the PMMA surface with the laser was modified into hydrophobic or hydrophilic by the existence of oil and water. In conclusion, our study successfully demonstrated the production of the ideal intraocular lens.